1. Field of the Invention
The present invention relates to a screen supporter, especially to a supporter in which the supporting torque generated by a torque device being capable of working with the downward-pressing torque of a screen at different positions.
2. Description of Related Art
With the rapid development of information technology, a flat display, such as a liquid crystal display, is commonly adopted in a television or a desktop computer, or even an all-in-one desktop computer with a touch control function. The liquid crystal display has to utilize a supporter for being properly placed on a desktop for operation; for illustrating a general structure of the supporter, we take the Taiwan Patent No. M263727, titled in “Rotation axis structure with gyration and lift” granted to the applicant of the present invention, as an example, the structure includes an inclined support member, the top of the support member is pivoted with an upper rack through an upper rotation shaft, and the upper rack is fastened at the backside of a screen, so the screen is enabled to rotate relative to the support member for forwardly/backwardly adjusting the viewing angle; the bottom of the support member is pivoted with a lower rack through a lower rotation shaft, so the support member is enabled to rotate relative to the lower rack for adjusting the height of the screen, and the lower rotation shaft is installed with a torsion spring for generating supporting torque, so during the height adjustment, the downward-pressing torque generated by the weight of the screen can be balanced with the supporting torque of the lower rotation shaft, i.e. the screen can be kept at the adjusted position and height. In addition, two lateral sides of the support member are respectively installed with a pull rod, the two pull rods are combined with the upper rotation shaft and the lower rotation shaft thereby forming a parallel four-rod linkage mechanism, so the angle of the screen can be kept while the height thereof being adjusted.
Moreover, for convenient storage and package, the screen and the support member can be rotated for folding, thereby reducing the occupied space, the inclined support member is forwardly rotated through the lower rotation shaft for lowering the height so as to be in a horizontal state, the screen is backwardly rotated through the upper rotation shaft so as to be in the horizontal state, so the whole structure can be folded for reducing the package volume. However, while lowering the height of the screen, the resilience force of the torsion spring installed in the lower rotation shaft would be gradually increased, the torque is also gradually increased, so when being rotated to a lower position, a greater downward-pressing force has to be applied for completely folding, therefore the operation is not easy to be carried out. After releasing the applied force, the torsion spring which has accumulated certain amount of energy is very likely to bounce the screen, so an additional fastening process is needed for preventing the screen from bouncing. If the screen is backwardly rotated to horizontal before lowering the height, or gradually and backwardly rotated to horizontal during the height adjustment process, the gravity center of the screen will be gradually moved backwardly, the downward-pressing torque is therefore gradually reduced, or increased first then reduced later; as such, the conventional torsion spring cannot meet the requirement of adjusting the supporting torque.